Treating hydrocarbon oils



Patented Mar. 6, 195 1 UNITED STATES PATENT OFFIC TREATING HYDRO CARBON OILS Theodore B. Tom, Hammond, lnd assignor to Standard Oil Company, Chicago, 111., a corporation of Indiana N Drawing. Application January 27, 1950, Serial No. 140,970

16 Claims. 01. 196-39) This invention relates to the treatment of light hydrocarbon oils and more particularly relates to the stabilization of light petroleum oils which have been sweetened with a copper compound.

Hydrocarbon oils, particularly light petroleum oils, such as kerosene, gasoline, naphtha and similar petroleum distillates, usually contain a variety of sulfur compounds which are undesirable from the viewpoint that they impart an unpleasant odor and corrosive properties to the petroleum oil. A number of methods are employed to remove these undesirable sulfur compounds or to convert the sulfur compound to form which do vide a method of stabilizing petroleum oils which have been subjected to treatment with a coppercontaining reagent. Another object of the invention is to provide a method of stabilizing copper-sweetened petroleum distillates. A further object 01' the invention is to provide an improved method of inhibiting the oxldative deterioration of copper-sweetened petroleum distillates. Still another ooJect or the invention is to provide a method of treating copper-sweetened petroleum distlllates to remove therefrom copper and/or copper compounds which promote the oxioative deterioration of such petroleum ollstillates. other ob ects and advantages of the herein described invention will become apparent as the description thereo proceeds.

In accordance with the present invention hydrocaroon oils, particularly petroleum oils, such as gasoline, kerosene, fuel oils, naphthas, and the line, whether obtained Irom straight run or cracking processes which have been subjected to treatment with a copper reagent to remove undesirable constituents therefrom or to convert such undesiraole constituents to unobjectionable Iorms, and which are normally susceptible to oxidative deterioration because of the presence of copper and/or copper compounds therein, can be stabilized against such oxidative deterioration by treatment with a water-soluble organo-substituted acid of arsenic selected from the class consisting of an organo-arsonic acid having the general formula R-l lS=X is an organo-arsinic acid having the general formula XH Ri ls=X l.

an organo-arsenic acid having the general formula an organo-arsinous acid having the general formula ills-XE 4 an organo-arsenous acid having the general formula ills-X R5 KB and mixtures thereof, in which R, R1, R2, R3, R4 and R5 are organo radicals selected from the group consisting of aliphatic, cycloaliphatic, aromatic, heterocyclic radicals and mixtures thereof, and X is at least one element selected from the class consisting of oxygen and sulfur.

The term organo-radical as used herein and in the appended claims includes organo radicals which may contain substituent groups, such as for example, oxy, hydroxyl, thio, amino, mercapto, halogen, or other groups.

Specific examples of compounds falling within the above-named arsenic compounds are the following:

Organo arsonic acids, e. g.- Benzylarsonic acid Butylarsonic acid Phenylarsonic acid Allylarsonic acid Octylarsonic acid Phenylthioarsonic acid Allylthioarsonic acid Butylthioarsonic acid Cetylarsonic acid Tolylarsonic acid Hydroxyphenylarsonic acid Terpenylarsonic acid Ethoxyphenylarsonic acid 3-amyl-4-hydroxyphenyl-arsonic acid, etc.

3 Organo thion-arsonic acid, e. g.-

I-Iexyl thion-arsonic acid Phenyl thion-arsonic acid, etc. Organo thion-thiol-arsonic acid, e. g.- Lauryl thion-thiol-arsonic acid Xylyl thion-thiol-arsonic acid, etc. Organo-trithio-arsonic acid, e. g.

Butyl-trithio-arsonic acid Phenyl trithio-arsonic acid, etc. Organo-monothiol-arsonic acid, e. g.-

Phenyl monothiol-arsonic acid Decyl monothiol-arsonic acid Xylyl monothiol-arsonic acid, etc; Organo dithiol-arsonic acid, e. g.-

Lauryl dithiol-arsonic acid Isoamyl dithiol-arsonic acid and'similar organo-deri'vatives of arsinic and thio arsinic acid, arsenic and thio-arsenic acid, arsinous and thio-arsinous acid, arsenous and thioarsenous acid. While all of the organo arsenic compounds of the above type are efiective for the herein described purpose, it is not to be implied that all are equivalent since the specific gravity of the various compounds varies to some extent.

The treatment with the organo-substituted acid of arsenic is carried out by contacting the hydrocarbon oil with the oil-immiscible solution of the organo substituted acid of arsenic, at a temperature of from about 35 F. to about 210 F., and preferably from about 60 F. to about 100 F., for a period sufiicient to remove the objectionable copper compounds. Usually, contact times of from about 0.5 minute to about 15 minutes will be found sufficient, contact times being dependent on the means employed to obtain most intimate contacts between the immiscible liquids. Solutions of from about 0.01% to about preferably from about 0.5% to about 5.0% concentration can suitably be used in accordance with the present invention. Oil-immiscible solutions of the organo-substituted acids of arsenic are, for example, solutions of the acid in water, alcohols, e. g. methanol, ethanol, etc., acetone-water mixtures, glycol-water mixture and other substantially oil-insoluble solvents.

The effectiveness of organo arsenic acids in stabilizing light petroleum oils which have been sweetened with a copper compound, is illustrated by the data in Table I, obtained by subjecting the following petroleum. distillate to oxidation stability tests, as determinedby the A.S.T.M.v Method D-525-46.

(A) A cataiytically cracked naphtha having a distillation range of from about 155 F. toabout 400 F., sweetened by vigorously stirring and bubbling oxygen through a slurry of one liter of'the naphtha and 8 grams of copper chloride-clay catalyst, consisting of 72% Attapulgus clay fines, 8% copper chloride and 20% water for 30- minutes, and filtering.

(B) A thermally cracked naphtha having a distillation range of from about 150 F. to about 385 F., sweetened in the same manner as sample A; and

(C) A thermally cracked naphtha having a distillation range of from about 145 F. to about 400 F., sweetened by contacting the naphtha with the copper-clay catalyst in the presence of oxygen with vigorous stirring for two and one-half hours at room temperatures.

Before subjecting each of the above-described copper sweetened naphthas to the oxidation stability test, 4 parts of each sample were shaken with .1 part of a 1% aqueous solution of various organo arsenic compounds for five minutes, the aqueous phase separated from the upper layer, and the latter filtered. Each of the treated sweetened samples was stored under a nitrogen atmosphere until tested.

The effectiveness of the organo arsenic compounds in increasing the oxidation stability of copper chloride sweetened light petroleum distillates is-indicated by the increase in theinduction period.

The effectiveness-of the organo' arsenic acids in stabilizing copper sweetened light petroleum distillat'es against color and gum forming bodies is illustrated by thedat'a in- Table II; These data were obtained by treatingtaheater oil having a distillationrange. of fromabout 340 F. to about 575 F.. with: a copper chloride clay catalyst and with an organo arsenic compound in the manner above described and determining; the color of the treatedheatenoilbeiore and after aging at 200 for twenty hours. The gum reported in Table II- was obtained according to A.S.T.M. Method D-381, modifiedby the use of preheated steam as a substitute for air and 500 F. operating temperature instead of 320 F.

While .1 have describedmyinventionby reference tospecific embodiments thereof, the invention is not to. be limited thereby, but includes within its scope such modifications as come withinv the spiritoithe appended claims.

1. The method of stabilizing a copper-contaminated hydrocarbon oil comprising mixing said oil with an oil-immiscible solution of an organosubstituted acid of arsenic selected from the class consisting of an organo arsenic acid having the general formula R-l s=X.

an organo-arsinic acid having the general formula XH Rr1 \s=X an organo-arsenic acid having the general formula an organo-arsenous acid having the general formula and mixtures thereof, in which R, R1, R2, R3, R4 and R5 are organo radicals selected from the group consisting of aliphatic, cycle-aliphatic, aromatic, heterocyclic radicals and mixtures thereof, and X is an element selected from the group consisting of oxygen and sulfur, and separating the oil-immiscible solution from the treated oil.

2. The method of stabilizing a copper-contaminated hydrocarbon oil comprising agitating a mixture of said oil and an oil-immiscible solution of an organo-substituted arsonic acid and separating the oil-immiscible solution from the treated oil.

3. The method of claim 2 in which the organosubstituted arsonic acid is an aliphatic-substituted arsonic acid.

4. The method of claim 3 in which the aliphatic-substituted arsonic acid is propylarsonic acid.

5. The method of claim 3 in which the allphatic-substituted arsonic acid is allylarsonic acid.

6. The method of claim 2 in which the organosubstituted arsonic acid is an aromatic-substituted arsonic acid.

7. The method of claim 6 in which the arcmatic-substituted arsonic acid is a phenylarsonic acid.

8. The method of claim 6 in which the arcmatic-substituted arsonic acid is para-hydroxy phenylarsonic acid.

9. The method of claim 2 substituted arsonic acid is stituted arsonic acid.

in which the organoa cyclo-aliphatic-sub- 10. The method of stabilizing a copper-containing hydrocarbon oil comprising agitating a mixture of said oil and an aqueous solution of organo substituted arsonic acid having a concentration of from about 0.01% to about 10% at a temperature of from about 35 F. to about 210 F., permitting the mixture to separate into an aqueous layer and an oil layer, and separating the aqueous solution from the treated oil.

11. The method of stabilizing a light petroleum distillate sweetened by treatment with a copper compound, comprising contacting said coppersweetened hydrocarbon petroleum distillate with an aqueous solution of an organo-substituted arsonic acid of from about 0.01% to about 10% concentration at a temperature of from about 35 F. to about 210 F., and separating the treated petroleum distillate from the aqueous solution.

12. The method of claim 11 in which the organo-substituted arsonic acid. is propylarsonic acid.

13. The method of claim 11 in which the organo-substituted arsonic acid is allylarsonic acid.

14. The method of claim 11 in which the organo-substituted arsonic acid is a phenylarsonic acid.

15. The method of claim 11 in which the organo-substituted arsonic acid is para-hydroxy phenylarsonic acid.

16. The method of stabilizing a copper chloride sweetened petroleum distillate comprising contacting said copper chloride sweetened petroleum distillate with an aqueous solution of an organosubstituted arsonic acid having a concentration within the range of from about 0.01% to about 10%, at a temperature of from about to about F., and separating the treated petroleum distillate from the aqueous solution.

THEODORE B. TOM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

1. THE METHOD OF STABILIZING A COPPER-CONTAMINATED HYDROCARBON OIL COMPRISING MIXING SAID OIL WITH AN OIL-IMMISCIBLE SOLUTION OF AN ORGANOSUBSTITUTED ACID OF ARSENIC SELECTED FROM THE CLASS CONSISTING OF AN ORGANO ARSONIC ACID HAVING THE GENERAL FORMULA 